Fusible links have been known to exist and are generally constructed on the principle of being temperature responsive and are held under tension or compression. At the appropriate temperature, the links then separate to enable the actuation of an alarm or other device in response to the occurrence of a predetermined temperature.
Generally, these fusible members (links) work on the same principle, that is they are held together by the eutectic solder or weld and liquify to enable the links to separate when the eutectic temperature is reached. Many different configurations of fusible links have been proposed and while the device is simple in construction, one or the other of previously employed links are unsatisfactory because they tend to "creep", i.e., they tend to allow slippage to occur between the fused parts rather than a clean separation. This means that at the eutectic temperature, instead of fully releasing, the fused parts will tend to move longitudinally without a clean break. In effect this is a malfunctioning of the fuse.
Also, by reason of the shape or configuration of the confronting surfaces of prior fuse elements, it has been found that the solder is unable to completely penetrate and fill the space between the confronting surfaces and consequently there develops voids which make it impossible to obtain a complete solder between the fusible links and thus no uniformity or precision in operation of the fuse is obtainable at the eutectic temperature. It is absolutely essential to obtain precise fuse operation and this is achieveable at least in part by a complete and uniform flux-and-soldering between the surfaces of the link elements.
Additionally, it is desired that there be some way of product identification on the link including trademark and tradename, product number, various approvals, all of which can conveniently be embossed on outer surfaces of the link if such surfaces are available. It is customary also to include, in addition to the manufacturer's logo, any testing laboratory approvals, the temperature at which the fuse should be operated, year of manufacture, etc., all of which are additional safety precautions.
Accordingly, it is an object of the present invention to provide an improved link which is manufacturable from a continuous and progressive die operation, cutting, shaping and forming the links, the end result of which is a pair of interfittable links including cam portions which insure break-away of the soldered connection whenever there is any relative longitudinal movement between the fuse links.
It is another object of the present invention to provide a pair of internested fuse links which can be fluxed and soldered without any voids, discontinuities or incomplete joinder between the confronting fused surfaces.
It is another object of the present invention to provide complementary interfitted fuse links which can be soldered together to provide a uniform fuse connection precisely separated at the eutectic temperature desired and characterized by provision of a substantial embossing area which can conveniently receive data thereon such as manufacturing year, release temperature, testing laboratory approvals, manufacture and the like.
Other objects and features of the present invention will become apparent from a consideration of the following description which proceeds with reference to the accompanying drawings, wherein a selected example embodiment of the invention is illustrated by way of example and not by way of limitation of the invention.